Lubricating oil



John D. Morgan,

Cities fiel'vice Oil South @range,

@ompany corporation oi Fe m 1 i No Brewing. Application March 2, 194? I Serial No.

8 Claims. 7 (Cl. 252-37) peratures.

The aeroplane is an example of a machine that is required to be operated through a wide range of temperatures. ,Some of the parts and the instruments on the planes must be lubricated and freely movable at temperatures as low as 50 F. and as high as 200 F.

The primary object of to has lubricating qualities over a wide range of temperature and is particularly adapted for use at low temperatures.

Mineral oil lubricants which have a low pour test and especially those lubricants that are mobile liquids at 50 F.

- Per cent by volume li'ributyl phosphate 78.00 Polymerized castor oil 20.00 Bead naphthenate 00.75 ?olane 1.00 iantolube #261 00.25

In place of thetributyl phosphate, triethyl hosphate may be substituted in the above formula.

The tributyl and triethyl phosphates have luricating nese liquids have a very low pour point characaristic. The mixture of the tributyl or trlethyl hosphates hich has a pourpo'int of 75 The polymerized castor oil is F. to 80 F.

N. 3., assignor to Hillside, N. 3., a nia merce which is an been given a heat tion of the oil. The ordinary castor oil is insoluble in mineral lubricating oilsbut the polymerized castor oil is soluble in mineral lubricating oils.

ordinary castor oil that has The heat treatment of the castor oil may be done under atmospheric pressure or under comparatively high pressure. In' either case the heat treatment should be carried out so that the temperature of the oil will not be carried above 570 F. The heat treatment of castor oil is preferably carried out in an inert atmosphere, such as carbon dioxide, or nitrogen, and this tends to destroy those portions of the castor oil that readily becomes rancid. The polymerized castor-oil has oiliness characteristics and extreme pressure characteristics. Furthermore it has pronounced film forming characteristics that provide a good coating or film on the parts to be lubricated.

The lead naphthenate is used in the above formula in a comparatively small amount and has the characteristic of giving the oil an adhesiveness or tackiness that helps it to adhere to the metal parts being lubricated to form a film. The mixture of tributyl phosphate and polymerized castor oil will adhere quite readily to metal parts at the low temperatures at which it is to be used. that is 0 to -40 F., but when it is heated to 200 F. the film becomes very thin or breaks.

with castor oil produces a product a product of com- The presence of lead naphthenatetends to form a continuous film at the higher temperatures and seems-t0 have a characteristic of maintaining a practically uniform thickness of film throughout the range of 40 F. to 200 F. Lead naphthenate is quite effective also in rendering the mixture of tributyl phosphate and polymerized castor oil non-corrosive.

The extreme pressure agent Polane, is a procluct sold Santolube #261 is an additive commonly used in modifying the properties of lubricating oils. additive is manufactured by the Monsanto taining compounds of tin and sulfur. This additive may be defined as a sulfurized tin salt of an alkyl phenol carboxylic acid. The percentage of tin and sulfur in the additive is 3.25 percent'and treatment to polymerize a por-' 0.8 percent by weight respectively. This additive is a pour point depressant and an antioxidant and acts also as an inhibitor for preventing corrosion to the metallic parts being lubricated.

The lubricating oil containing tributyl phosphate as outlined in the formula above is a stable liquid at temperatures of 200 F. and above. This liquid has the following Saybolt viscosity characteristics:

Degrees Fahrenheit 1350 seconds at 40 270 seconds at Q.

62 seconds at '77 52 seconds at 100. 35 seconds at -Q 200 The viscosity of the product containing triethyl phosphate is considerably lower throughout the temperature range of 40 F. to 200 F. I

The preferred form of the invention having been thus described, what is claimed as new is:

1. A wide range of temperature lubricant con sisting of a major portion of tributyl phosphate and polymerized castor oil inhibited against oxidation and corrosion.

2. A wide range of temperature lubricant consisting of approximately one part ofvpolymerized castor oil to four parts of tributyl phosphate which is inhibited against oxidation and corrosion by a small amount of an ester of a fatty acid and a silfurized tin salt of an alkyl phenol carboxylic aci 3. A wide range of temperature lubricant consisting of a major portion of triethyl phosphate and polymerized castor oil inhibited against oxidation and corrosion.

4. A wide range of temperature lubricant consisting of a major portion of tributyl phosphate and polymerized castor oil, a minor portion of an extreme pressure additive, said mixture being inhibited against oxidation and corrosion.

5. A wide range of temperature lubricant consisting of essentially tributyl phosphate and polymerized castor oil to which are added minor portions of lead naphthenate, an ester of a fatty acid and a sulfurized tin salt of an alkyl phenol carboxylic acid.

6. A wide range of temperature lubricant comprising tributyl phosphate '78 percent by volume, polymerized castor oil 20 percent by volume, lead naphthenate 0.75 percent by volume, an ester of a fatty acid 1 percent by volume, and a sulfurized tin salt of an alkyl phenol carboxylic acid 0.25 percent by volume.

7. A widerange of temperature lubricant having a pour point below 60 F. consisting of a mixture of tributyl phosphate and polymerized castor oil inhibited against oxidation and having a viscosity of approximately 1350 seconds at -40 F. and seconds at 200 F.

8. A wide range of temperature lubricant consisting of a major portion of a trialkyl phosphate and polymerized castor oil inhibited against oxidation and corrosion and having substantial film forming characteristics in the temperature range of F. to 200 F.

JOHN D. MORGAN. 

